lux

Also known as lx

The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI). It is equal to one lumen per square metre. In photometry, this is used as a measure of the irradiance, as perceived by the spectrally unequally responding human eye, of light that hits or passes through a surface. It is analogous to the radiometric unit watt per square metre, but with the power at each wavelength weighted according to the luminosity function, a model of human visual brightness perception, standardized by the CIE and ISO. In English, "lux" is used as both

AI overview

Lux is the standard unit for measuring how brightly light illuminates a surface, defined as one lumen of light per square meter. It matters because it accounts for how the human eye actually perceives brightness across different colors of light, making it useful for practical applications like lighting design and photography where human vision is the relevant concern.

AI-generated from the Wikipedia summary — may contain errors.

Key facts

Unit.name: lux
Unit.image: Lux meter.jpg
Unit.caption: A lux meter for measuring illuminance
Unit.standard: SI
Unit.quantity: illuminance
Unit.symbol: lx
Unit.units1: SI base units
Unit.inunits1: cd⋅sr⋅m−2
Unit.units2: US customary units
Unit.inunits2: 0.0929 fc
Unit.units3: CGS units

via Wikipedia infobox

Wikidata facts

Image: Lux meter.jpg

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Wikidata SPARQL query equivalent: wd:Q179836 p:P2370/psn:P2370 [wikibase:quantityAmount ?source; wikibase:quantityUnit ?base]. ?item p:P2370/psn:P2370 [wikibase:quantityAmount ?target; wikibase:quantityUnit ?base]. BIND(?source / ?target as ?value)
conversion to SI unit: 1
conversion to standard unit: 0.0001
unit symbol: lx

Sources (1)

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Article

10 sections

Contents

Explanation
Illuminance
Relationship between illuminance and irradiance
Use in video-camera specifications
Non-SI units of illuminance
Legacy Unicode symbol
SI photometry units
See also
References
External links

==Explanation== ===Illuminance=== Illuminance is a measure of how much luminous flux is spread over a given area. One can think of luminous flux (with the unit lumen) as a measure of the total "amount" of visible light present, and the illuminance as a measure of the intensity of illumination on a surface. A given amount of light will illuminate a surface more dimly if it is spread over a larger area, so illuminance is inversely proportional to area when the luminous flux is held constant.